Two-dimensional solid-state image capture device with polarization member and color filter for sub-pixel regions and polarization-light data processing method therefor

ABSTRACT

A two-dimensional solid-state image capture device includes pixel areas arranged in a two-dimensional matrix, each pixel area being constituted by multiple sub-pixel regions, each sub-pixel region having a photoelectric conversion element. A polarization member is disposed at a light incident side of at least one of the sub-pixel regions constituting each pixel area. The polarization member has strip-shaped conductive light-shielding material layers and slit areas, provided between the strip-shaped conductive light-shielding material layers. Each sub-pixel region further has a wiring layer for controlling an operation of the photoelectric conversion element, and the polarization member and the wiring layer are made of the same material and are disposed on the same virtual plane.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a two-dimensional solid-state imagecapture device and a polarization-light data processing method therefor.

2. Description of the Related Art

Two-dimensional solid-state image capture devices that obtain imagesthrough photography of subjects by using photoelectric conversionelements including two-dimensional solid-state image capture elementsare increasingly used. Examples include a digital still camera, a videocamera, and a camcorder (which is an integration of a photographing unit(such as a video camera) and a recording unit, and which is anabbreviation of a camera and recorder). CCD (charge coupled device)image capture elements and CMOS (complementary metal oxidesemiconductor) image capture elements, which are solid-state imagecapture elements mainly used today, have sensitivities in a wide rangefrom a visible-light wavelength to a near-infrared-light wavelength andcan render vivid color images. The photoelectric conversion elements,however, have no intrinsic sensitivity to polarization. That is, thesituation of the currently available two-dimensional solid-state imagecapture devices is that polarization information provided by light isunutilized and eliminated.

Although the sunlight is unpolarized, light resulting from reflectionand dispersion of the sunlight contains polarization components thatdepend on the surface state of a reflection surface. For example, thesky during the daytime, snowy scenery, or the like contains a largeamount of polarization component polarized in a particular direction. Inaddition, during photography across an “interface”, for example, duringphotography in which glass of a show window or the like is interposed orduring photography at the surface of water, the surface of a lake, orthe like, separation of polarization components and non-polarizationcomponents makes it possible to improve the image contrast and alsomakes it possible to eliminate unwanted information. For example, apolarization element can be advantageously used, for example, when it isdesired to make a blue sky in a landscape picture to appear moreultramarine or it is desired to eliminate reflection components in ashow window.

In general, in order to separate polarization components andnon-polarization components, a polarizing (PL) filter is provided at thefrontside of a lens and photography is performed with the polarizationcomponents being emphasized or attenuated through rotation of thepolarizing filter. In terms of usability, however, such a scheme hassome problems, for example, as follows.

[1] The polarization filter can only obtain polarization components inone direction at the same time.[2] Only one type (one direction) polarization information can beobtained with the entire screen.[3] Emphasis and attenuation of polarization components generally haveto be adjusted through rotation of the polarizing filter.

The number of solid-state image-capture element pixels for use in theabove-described two-dimensional solid-state mage capture devicetypically exceeds 10 millions. Due to a lithography-basedmicrofabrication technology with advancement and improvement ofsemiconductor manufacturing processes, microstructures on asub-100-nanometer scale have become feasible. Based on such atechnological background, development and study of a solid-state imagecapture element that is capable of simultaneously obtaining polarizationinformation, in addition to the capability of general photography, arealso underway.

For example, Japanese Unexamined Patent Application Publication No.2007-086720 discloses a device that simultaneously obtains polarizationdirections in four directions and intensities regarding polarizationcomponents (the intensities may hereinafter be referred to as“polarization component intensities”) to thereby obtain a polarizationdirection and a polarization component intensity. Japanese UnexaminedPatent Application Publication (Translation of PCT Application) No.2007-501391 discloses a method and an optical element which causesurface plasmon polaritons in a wire grid (a conductor lattice).

Wire-grid polarization members have been used in a band ofelectromagnetic waves (e.g., mainly, microwaves, millimeter waves, andsub-millimeter waves) having longer wavelengths than visible-lightwavelengths and have long been available as elements for separatingfrequencies and obtaining polarization components. In order to performpolarization component separation by using wire-grid polarizationmembers, it is generally necessary to provide a wire grid with aninterval (pitch) that is substantially the same as or smaller than thewavelength of electromagnetic waves. Thus, until recent years, it hadbeen difficult to realize polarization members that are suitable for usein a visible-light wavelength band with wavelengths of 400 to 700 nm.However, with advancement and improvement of semiconductor manufacturingprocesses, polarization members that have reached the sufficientlypracticable level even in a visible-light wavelength band are currentlyavailable. Future application of such wire-grid (conductor-lattice)polarization members is expected.

SUMMARY OF THE INVENTION

The technology disclosed in Japanese Unexamined Patent ApplicationPublication No. 2007-086720 is mainly aimed to use, as a polarizationmember, a multilayer film (photonic crystal) in which two types ofoptical member having different refractive indices are stacked in anincident-light propagation direction, in order to obtain a polarizationdirection and a polarization component intensity. The multilayer filmhas a basic structure with an optical film thickness corresponding toone-fourth the incident wavelength. That is, one period of themultilayer film corresponds to the optical film thickness of a halfwavelength. Such periodic structures are stacked to have about 10 layersin order to realize a polarization-light detection function, thethickness of the polarization member becomes at least a few micrometers.As the thickness of the polarization element increases,oblique-incident-light-induced color mixture with neighborhood pixelsand a sensitivity decrease due to attenuation/diffusion of lightpropagating in a medium become more problematic. Japanese UnexaminedPatent Application Publication No. 2007-086720 proposes the use of awire grid (a conductor lattice) as the polarization member, but includesno specific description on the material, the line width, the arrangementposition, and so on of the wire grid. Hence, the technology lacksfeasibility. On the other hand, Japanese Unexamined Patent ApplicationPublication (Translation of PCT Application) No. 2007-501391 employs awire grid (a conductor lattice) as an optical element for a near-fieldlight detection sensor, but is not aimed to obtain polarizationinformation and also does not explain a method for disposing three ormore types of polarization element used for obtaining polarizationinformation and an algorithm used for extracting the polarizationinformation.

In the device disclosed in Japanese Unexamined Patent ApplicationPublication No. 2007-086720, one pixel area is constituted by foursub-pixel regions, each having a wire-grid polarization member. Lightfrom the polarization member provided in each sub-pixel region isdetected by a photoelectric conversion element. This arrangement hassome problems. For example, the amount and intensity of light receivedby the photoelectric conversion element included in each sub-pixelregion decreases (i.e., the sensitivity decreases) compared to a case inwhich no polarization member is provided. Moreover, the rate of decreasevaries from one sub-pixel region to another. Additionally, thecomputation processing for the amount and intensity of light received bythe photoelectric conversion element in each sub-pixel region becomescomplicated. In the devices disclosed in the above-describedpublications, no description has been given of the positionalrelationship between the wire-grid polarization member and a wiringlayer for controlling an operation of the photoelectric conversionelement, the positional relationship between the wire-grid polarizationmember and a light-shielding layer for controlling (restricting)incidence of light on the photoelectric conversion element, and thepositional relationship between the wire-grid polarization member and acolor filter.

Accordingly, it is desirable to provide a two-dimensional solid-stateimage capture device having an optimized positional relationship betweenthe wire-grid polarization member and the wiring layer for controllingthe operation of the photoelectric conversion element, an optimizedpositional relationship between the polarization member and thelight-shielding layer for controlling (restricting) incidence of lighton the photoelectric conversion element, and an optimized positionalrelationship between the polarization member and the color filter. It isalso desirable to provide a two-dimensional solid-state image capturedevice having a configuration and a structure with which a decrease inthe sensitivity is unlikely. It is further desirable to provide apolarization-light data processing method that is applied for atwo-dimensional solid-state image capture device having a configurationand a structure with which a decrease in the sensitivity is unlikely andthat does not complicate computation processing for the amount andintensity of light received by the photoelectric conversion element.

A two-dimensional solid-state image capture device according to first tofourth modes of the present invention includes: pixel areas arranged ina two-dimensional matrix, each pixel area being constituted by multiplesub-pixel regions, each sub-pixel region having a photoelectricconversion element. The polarization member has strip-shaped conductivelight-shielding material layers and slit areas, provided between thestrip-shaped conductive light-shielding material layers, to transmitlight having a polarization component in a direction perpendicular to adirection in which the strip-shaped conductive light-shielding materiallayers extend and to suppress transmission of light having apolarization component in a direction parallel to the direction in whichthe strip-shaped conductive light-shielding material layers extend.

In the two-dimensional solid-state image capture device according to thefirst mode of the present invention, a polarization member is disposedat a light incident side of at least one of the sub-pixel regionsconstituting each pixel area, each sub-pixel region further has a wiringlayer for controlling an operation of the photoelectric conversionelement, and the polarization member and the wiring layer are made ofthe same material and are disposed on the same virtual plane.

In the two-dimensional solid-state image capture device according to thesecond mode of the present invention, a polarization member is disposedat a light incident side of at least one of the sub-pixel regionsconstituting each pixel area, each sub-pixel region further has alight-shielding layer for controlling (restricting) incidence of lighton the photoelectric conversion element, and the polarization member andthe light-shielding layer are disposed on the same virtual plane.

In the two-dimensional solid-state image capture device according to thethird mode of the present invention, a polarization member is disposedat a light incident side of one of the sub-pixel regions constitutingeach pixel area, a color filter is disposed at a light incident side ofa remaining sub-pixel region, and the color filter and the polarizationmember are disposed on the same virtual plane.

In the two-dimensional solid-state image capture device according to thefourth mode of the present invention, a polarization member is disposedat a light incident side of one of the sub-pixel regions constitutingeach pixel area, and a pixel-area group is constituted by Q₀ pixel areas(where Q₀≦3) and satisfies

θ_(q)=θ₁+(180/Q)×(q−1) (degree),

where Q indicates a positive integer (where 3≦Q≦Q₀), θ₁ indicates anangle defined by a predetermined direction and a direction in which thestrip-shaped conductive light-shielding material layers extend in thepolarization member in the sub-pixel region included in the q-th pixelarea (where q=1), and θ_(q) indicates an angle defined by apredetermined direction and a direction in which the strip-shapedconductive light-shielding material layers extend in the polarizationmember in the sub-pixel region included in the q-th pixel area (where2≦q≦Q) selected from the Q−1 pixel areas selected from the pixels areasother than the first pixel area.

A polarization-light data processing method for a two-dimensionalsolid-state image capture device according to a first or second mode ofthe present invention includes is directed to a two-dimensionalsolid-state image capture device including pixel areas arranged in atwo-dimensional matrix, each pixel area being constituted by multiplesub-pixel regions, each sub-pixel region having a photoelectricconversion element. A polarization member is disposed at a lightincident side of one of the sub-pixel regions constituting each pixelarea. The polarization member has strip-shaped conductivelight-shielding material layers and slit areas, provided between thestrip-shaped conductive light-shielding material layers, to transmitlight having a polarization component in a direction perpendicular to adirection in which the strip-shaped conductive light-shielding materiallayers extend and to suppress transmission of light having apolarization component in a direction parallel to the direction in whichthe strip-shaped conductive light-shielding material layers extend. Apixel-area group is constituted by Q₀ pixel areas (where Q₀≦3) andsatisfies

θ_(q)=θ₁+(180/Q)×(q−1) (degree),

where Q indicates a positive integer (where 3≦Q≦Q₀), θ₁ indicates anangle defined by a predetermined direction and a direction in which thestrip-shaped conductive light-shielding material layers extend in thepolarization member in the sub-pixel region included in the q-th pixelarea (where q=1), and θ_(q) indicates an angle defined by apredetermined direction and a direction in which the strip-shapedconductive light-shielding material layers extend in the polarizationmember in the sub-pixel region included in the q-th pixel area (where2≦q≦Q) selected from the Q−1 pixel areas selected from the pixels areasother than the first pixel area.

The polarization-light data processing method for the two-dimensionalsolid-state image capture device according to the first mode of thepresent invention includes the steps of determining, as an angle θ_(max)at which a maximum value in a sine function obtained based on a lightintensity I_(q) is obtained, a polarization direction θ_(PL-max) inwhich a maximum polarization intensity I_(PL-max) of light that isincident on the pixel area is obtained, wherein the light intensityI_(q) represents a light intensity of light that is incident on thesub-pixel region that has the polarization member and that is includedin the q-th pixel area (where q=1, 2, . . . , Q); and using thedetermined maximum value and a minimum value in the sine function as themaximum polarization intensity I_(PL-max) and a minimum polarizationintensity I_(PL-min) of light that is incident on the pixel area.

The polarization-light data processing method for the two-dimensionalsolid-state image capture device according to the second mode of thepresent invention includes the steps of: using, as a maximumpolarization intensity I_(PL-max) of light that is incident on the pixelarea, a maximum value I_(max) of a light intensity I_(q) of light thatis incident on the sub-pixel region that has the polarization member andthat is included in the q-th pixel area (where q=1, 2, . . . , Q);using, as a polarization direction θ_(PL-max) in which the maximumpolarization intensity I_(PL-max) of light that is incident on the pixelarea is obtained, an angle θ_(q) of the pixel area where the maximumvalue I_(max) is obtained; and using a minimum value I_(min) of thelight intensity I_(q) as a minimum polarization intensity of light thatis incident on the pixel area.

In the two-dimensional solid-state image capture device according to thefirst mode of the present invention, the polarization member and thewiring member for controlling the operation of the photoelectricconversion element are made of the same material and are disposed on thesame virtual plane. Thus, the wiring layer and the polarization membercan be simultaneously formed in the same process. That is, thepositional relationship between the wire-grid polarization member andthe wiring layer in the manufacturing process is optimized, thus makingit possible to provide the polarization member without an increase inthe number of manufacturing processes and making it possible to reducethe manufacturing cost of the two-dimensional solid-state image capturedevice. In the two-dimensional solid-state image capture deviceaccording to the second mode of the present invention, the polarizationmember and the light-shielding layer for controlling (restricting)incidence of light on the photoelectric conversion element are disposedon the same virtual plane. Thus, the light-shielding layer and thepolarization member can be simultaneously formed in the same process.That is, the positional relationship between the wire-grid polarizationmember and the light-shielding layer in the manufacturing process isoptimized, thus making it possible to reduce the manufacturing cost ofthe two-dimensional solid-state image capture device. Thus, thetwo-dimensional solid-state image capture device according to the firstor second mode of the present invention can be manufactured using ageneral semiconductor-device manufacturing process. Moreover, since itis not necessary to add another layer for the polarization member, it ispossible to achieve a lower-profile structure of the two-dimensionalsolid-state image capture device. The provision of the polarizationmember also does not involve an increase in the thickness of thetwo-dimensional solid-state image capture device. In addition, in thetwo-dimensional solid-state image capture device in the third mode ofthe present invention, the color filter and the polarization member aredisposed on the same virtual plane. Thus, it is unlikely that the heightof the sub-pixel region having the polarization member and the height ofanother sub-pixel region having the color filters differ from eachother. Since the thickness of the polarization member in thetwo-dimensional solid-state image capture device in each of the first tothird modes of the present invention can be reduced to as small as about0.1 μm, it is possible to more realizably achieve a lower-profilestructure of the two-dimensional solid-state image capture device.

The polarization member transmits only polarization components in aparticular direction and reflects and absorbs other polarizationcomponents. Thus, the sub-pixel region having the polarization memberhas a problem in that the sensitivity decreases compared to thesub-pixel region having no polarization member. In the two-dimensionalsolid-state image capture device according to the fourth mode of thepresent invention and the two-dimensional solid-state image capturedevice in the polarization-light data processing method according to thefirst or second mode of the present invention, the polarization memberis disposed at the light incident side of one of the multiple (M₀)sub-pixel regions constituting each pixel area and Q polarizationmembers (where Q≦Q₀) are disposed in the pixel-area group constituted byQ pixel areas (where Q₀≦3). That is, only Q polarization members aredisposed in the total of Q₀×M₀ sub-pixel regions constituting onepixel-area group. Consequently, it is possible to minimize a sensitivityreduction due to the arrangement of the polarization members in theentire pixel area. Determination of the polarization direction and theintensity of polarization components (the polarization componentintensity) at the position of each pixel area by performinginter-pixel-area computation processing makes it possible to obtainpolarization information with the spatial resolution being slightlycompromised, while minimizing a reduction in the sensitivity. Since onlyQ polarization members are disposed in the total of Q₀×M₀ sub-pixelregions constituting one pixel-area group, the computation processingfor the amount and intensity of light received by the photoelectricconversion elements does not become complicated.

A system in which one polarizing filter is disposed over the entiresurface of a lens has been mainly used as a polarizing filter.Therefore, polarization components in only one direction can be obtainedfor a single image, and thus, the polarizing filter typically has to berotated to obtain multiple images in order to obtain information of thepolarization component intensity and the polarization direction. Thatis, it is practically very difficult to obtain information of thepolarization component intensity, the polarization direction, and so onin real time. Also, in the two-dimensional solid-state image capturedevice of the present invention, the polarization members havingdifferent azimuths are disposed in the pixel areas. Thus, it is possibleto obtain information of the polarization direction and the polarizationcomponent intensity from a single image and it is also possible toindividually obtain information of the polarization directions and thepolarization component intensities from various areas and portions in asingle image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are partial cross-sectional views schematically showinga two-dimensional solid-state image capture device in a firstembodiment;

FIGS. 2A and 2B are partial cross-sectional views schematically showinga two-dimensional solid-state image capture device in a thirdembodiment;

FIGS. 3A and 3B are partial cross-sectional views schematically showinga two-dimensional solid-state image capture device in a fourthembodiment;

FIGS. 4A and 4B are partial schematic plan views of a polarizationmember;

FIG. 5 schematically shows a plan layout view of sub-pixel regions inthe first embodiment;

FIG. 6 schematically shows a plan layout view of the sub-pixel regionsin the first embodiment;

FIG. 7 schematically shows a plan layout view of the sub-pixel regionsin the first embodiment;

FIG. 8 schematically shows a plan layout view of the sub-pixel regionsin the first embodiment;

FIG. 9 schematically shows a plan layout view of the sub-pixel regionsin the first embodiment;

FIG. 10 schematically shows another plan layout view of the sub-pixelregions in the first embodiment;

FIG. 11 schematically shows a plan layout view of sub-pixel regions in atwo-dimensional solid-state image capture device to which thetwo-dimensional solid-state image capture devices according to the firstto third modes of the present invention are applicable;

FIG. 12 schematically shows another plan layout view of the sub-pixelregions in the two-dimensional solid-state image capture device to whichthe two-dimensional solid-state image capture devices according to thefirst to third modes of the present invention are applicable; and

FIG. 13 is a conceptual view illustrating light that passes through awire-grid (conductor-lattice) polarization member and so on.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described below in conjunction withembodiments with reference to the accompanying drawings. The presentinvention, however, is not limited to the embodiments and variousnumeric values and materials in the embodiments are illustrative. Adescription below is given in the following sequence:

1. Two-Dimensional Solid-State Image Capture Device according to Firstto Fourth Modes of Present Invention, Polarization-light data processingMethod for Two-Dimensional Solid-State Image Capture Device according toFirst and Second Modes of Present Invention, and Overall Technology,

2. First Embodiment (Two-Dimensional Solid-State Image Capture Deviceaccording to First and Fourth Modes of Present Invention andPolarization-light data processing Method for Two-DimensionalSolid-State Image Capture Device according to First Mode of PresentInvention),

3. Second Embodiment (Polarization-light data processing Method forTwo-Dimensional Solid-State Image Capture Device according to SecondMode of Present Invention),

4. Third Embodiment (Two-Dimensional Solid-State Image Capture Deviceaccording to Second Mode of Present Invention), and

5. Fourth Embodiment (Two-Dimensional Solid-State Image Capture Deviceaccording to Third Mode of Present Invention, Etc.).

[Two-Dimensional Solid-State Image Capture Device According to First toFourth Modes of Present Invention, Polarization-Light Data ProcessingMethod for Two-Dimensional Solid-State Image Capture Device According toFirst and Second Modes of Present Invention, and Overall Technology]

In a two-dimensional solid-state image capture device according to firstto fourth modes of the present invention and a two-dimensionalsolid-state image capture device in a polarization-light data processingmethod according to first and second modes of the present invention,multiple pixel areas are generally arranged in a two-dimensional matrixin an X direction and a Y direction.

In the two-dimensional solid-state image capture device according to thesecond mode of the present invention, each sub-pixel region may have atleast one wiring layer for controlling an operation of a photoelectricconversion element, and a polarization member and the wiring layer maybe made of the same material and may be disposed on the same virtualplane. In such a case, it is preferable to use a color filter having aconductor-lattice structure.

In the two-dimensional solid-state image capture device according to thefourth mode of the present invention and the polarization-light dataprocessing method for the two-dimensional solid-state image capturedevice according to the first and second modes of the present invention,Q may be 4 but is not limited thereto. In this case, for Q=4, it followsthat: θ₂=θ₁+45 (degree), θ₃=θ₁+90 (degree), and θ₄=θ₁+135 (degree). ForQ=3, it follows that: θ₂=θ₁+60 (degree) and θ₃=θ₁+120 (degree). For Q=6,it follows that: θ₂=θ₁+30 (degree), θ₃=θ₁+60 (degree), θ₄=θ₁+90(degree), θ₅=θ₁+120 (degree), and θ₆=θ₁+150 (degree). For aconfiguration with Q₀=4, for example, each pixel-area group can beconstituted by four (2×2) pixel areas; for a configuration with Q₀=6,each pixel-area group can be constituted by six (2×3) pixel areas; andfor a configuration with Q₀=9, each pixel-area group can be constitutedby nine (3×3) pixel areas.

The two-dimensional solid-state image capture device according to thefourth mode of the present invention including the above-describedpreferred configuration or the two-dimensional solid-state image capturedevice in the polarization-light data processing method according to thefirst and second modes of the present invention can also be combinedwith the two-dimensional solid-state image capture device according tothe first mode of the present invention. That is, the sub-pixel regionsmay also take a form in which each sub-pixel region has at least onewiring layer for controlling the operation of the photoelectricconversion element and the polarization member and the wiring layer aremade of the same material and are disposed on the same virtual plane.Alliteratively, the two-dimensional solid-state image capture deviceaccording to the fourth mode of the present invention including theabove-described preferred configuration or the two-dimensionalsolid-state image capture device in the polarization-light dataprocessing method according to the first and second modes of the presentinvention can be combined with the two-dimensional solid-state imagecapture device according to the second mode of the present invention.That is, the sub-pixel regions may also take a form in which eachsub-pixel region has a light-shielding layer for controlling(restricting) incidence of light on the photoelectric conversion elementand the polarization member and the light-shielding layer are disposedon the same virtual plane. Alliteratively, the two-dimensionalsolid-state image capture device according to the fourth mode of thepresent invention including the above-described preferred configurationor the two-dimensional solid-state image capture device in thepolarization-light data processing method according to the first andsecond modes of the present invention can be combined with thetwo-dimensional solid-state image capture device according to the thirdmode of the present invention. That is, the sub-pixel regions may alsotake a form in which a color filter is disposed at the light incidentside of the sub-pixel region having no polarization member and the colorfilter and the polarization member are disposed on the same virtualplane.

In the polarization-light data processing method for the two-dimensionalsolid-state image capture device according to the first mode of thepresent invention, the two-dimensional solid-state image capture devicemay take a form in which the direction and the intensity of polarizationcomponents (the intensity may be referred to as a “polarizationcomponent intensity”) of light that is incident on, of the sub-pixelregions constituting each pixel area, the sub-pixel region having nopolarization member are corrected based on the light intensityI_(PL-max) and/or the light intensity I_(PL-min). In this case, it ispreferable that the direction and the intensity of the polarizationcomponents (the polarization component intensity) of light that isincident on, of the sub-pixel regions constituting each pixel area, thesub-pixel region having no polarization member be corrected based on thelight intensity I_(PL-max) and/or the light intensity I_(PL-min) derivedfrom the sub-pixel regions that have the polarization members and thatare located in the vicinity of the sub-pixel region having nopolarization member. Alternatively, in the polarization-light dataprocessing method for the two-dimensional solid-state image capturedevice according to the first mode of the present invention, thetwo-dimension solid-state image capture device may take a form in whichthe light intensity I_(q) of light that is incident on the sub-pixelregion having the polarization member, the sub-pixel region beingincluded in the q-th pixel area (where q=1, 2, . . . , Q), is correctedbased on the light intensities of light that is incident on theneighborhood sub-pixel regions that have no polarization members andthat have the same detection wavelength band as the sub-pixel regionhaving the polarization member.

In the two-dimensional solid-state image capture device according to thefirst to fourth modes of the present invention including theabove-described preferred forms and configurations and thetwo-dimensional solid-state image capture device in thepolarization-light data processing method according to the first andsecond modes of the present invention (hereinafter, these devices maycollectively be referred to as a “two-dimensional solid-state imagecapture device of the present invention”), one sub-pixel region has onephotoelectric conversion element, which may be implemented as, forexample, a CCD, CMOS, or CMD (charge modulation device)signal-amplifying image sensor.

The polarization member (polarization element) in the two-dimensionalsolid-state image capture device of the present invention hasstrip-shaped conductive light-shielding material layers and slit areasprovided between the conductive light-shielding material layers.Material for the conductive light-shielding material layers may be aconductive material having a complex refractive index that is low in therange of wavelengths to which the photoelectric conversion element issensitive. Examples of the material include aluminum (Al), copper (Cu),gold (Au), silver (Ag), platinum (Pt), tungsten (W), and an alloycontaining such metal. Alternatively, the strip-shaped conductivelight-shielding material layers can be provided by arranging lineelements, such as carbon nanotubes, in a lattice or can be provided byarranging or printing nanoparticles of gold, silver, CdSe (cadmiumselenide), or the like in a lattice. The formation pitch P₀ of thestrip-shaped conductive light-shielding material layers is, for example,one-half or one-twentieth the wavelength of incident light. The widthW_(s) of the slit areas (i.e., a dimension in a direction perpendicularto a direction in which the conductive light-shielding material layersextend) and the width W_(c) of the strip-shaped conductivelight-shielding material layers satisfy the relationship of, forexample, 0.5W_(c)≦W_(s)≦5W_(c). It is desired that W_(s) be larger thanor equal to 5×10⁻⁸ m. Examples of a method for fabricating thepolarization member include a technique for depositing conductivelight-shielding material layers, a combination of a lithographytechnique and a conductive light-shielding material-layer patterningtechnique (e.g., a physical etching technique or an anisotropic etchingtechnique or using carbon tetrafluoride gas, sulfur hexafluoride gas,tifluoromethane, xenon difluoride, or the like) using an etchingtechnique, a combination of a lithography technique and a technique forforming protrusion/depression portions of a base by using an etchingtechnique and for depositing conductive light-shielding material layersat the top surfaces of protrusion portions of the base, and theso-called “lift-off technique”. Examples of the method for depositingthe conductive light-shielding material layers include, not onlyphysical vapor deposition (PVD) such as vacuum deposition andsputtering, but also chemical vapor deposition (CVD), plating,metalorganic chemical vapor deposition (MOCVD), and molecular beamepitaxy (MBE). Examples of the lithography technique include anelectron-beam lithography technique, X-ray lithography, and aphotolithography technique (i.e., a lithography technique using a g-rayor i-ray of a high-pressure mercury vapor lamp, a krypton fluoride (KrF)excimer laser, an argon fluoride (ArF) excimer laser, or the like as alight source). Alternatively, the strip-shaped conductivelight-shielding material layers can be formed by a nanoimprinting methodor a microfabrication technology using an ultra-short-duration pulselaser, such as a femtosecond laser. Each slit area may have an elongatedrectangular shape in plan view, but is not limited thereto. For example,each slit area may have a set of rectangular openings. In this case,however, the dimension of the longitudinal axis (i.e., a direction inwhich the strip-shaped conductor light-shielding material layers extend)of each rectangle generally has to be significantly larger than theeffective wavelength of light that has a wavelength of λ₀ and that isincident on the slit area (λ₀/n₀, where n₀ denotes the refractive indexof a medium contained in the slit area). It is preferable that the slitarea be filled with, for example, an incident-light-transmissive medium(dielectric material), such as a silicon oxide film or silicon nitridefilm. The medium, however, is not limited to this example, and the slitarea may be filled with air or nonconductive fluid. When visible lightwavelengths are considered by way of example, wavelengths λ_(R), λ_(G),and λ_(B) of red, green, and blue are in the range of approximately 600to 800 nm, 500 to 600 nm, and 380 to 500 nm, respectively. Thus, thewavelengths λ′_(R), λ′_(G), and λ′_(B) in the medium when the refractiveindex of the medium is assumed to be 1.5 are in the range of 400 to 530nm, 330 to 400 nm, and 250 to 330 nm, respectively, and it is desirablethat the formation pitch P₀ of the strip-shaped conductivelight-shielding material layers be one-half the wavelengths λ′_(R),λ′_(G), and λ′_(B) or smaller. It is also preferable that the thicknessof the conductive light-shielding material layers be 1 μm or less. Sinceincident light is not shielded if the thickness of the conductivelight-shielding material layers is too small, the lower limit of thethickness thereof is preferably be set to be large enough tosufficiently shield incident light.

In the two-dimensional solid-state image capture device according to thefirst and second modes of the present invention, a polarization memberis disposed at the light incident side of at least one of multiple (M₀)sub-pixel regions constituting each pixel area. More specifically, whenthe number of sub-pixel regions in which the polarization members aredisposed is indicated by m₀, it is preferable that the value of m₀ be 1.The value of m₀, however, is not limited to 1, and may be 2 or more ormay be M₀ or less.

In the preferred form of two-dimensional solid-state image capturedevice according to the first mode of the present invention and thetwo-dimensional solid-state image capture device according to the fourthmode of the present invention, the polarization member and the wiringlayer are made of the same material. Specific examples of the materialinclude aluminum (Al) and copper (Cu). The “virtual plane” on which boththe polarization member and the wiring layer are disposed refers to avirtual plane containing bumps and dips which can be generated duringmanufacture.

In the preferred form of the two-dimensional solid-state image capturedevice according to the second mode of the present invention and thetwo-dimensional solid-state image capture device according to the fourthmode of the present invention, the light-shielding layer is provided.Specific examples of material for the light-shielding layer includealuminum (Al), copper (Cu), and tungsten (W). Any member thatefficiently reflects and absorbs incident light and that has asufficient light-shielding characteristic can be used as thelight-shielding member. The light-shielding layer and the polarizationmember can also be made of the same material. The “virtual plane” onwhich both the polarization member and the light-shielding layer aredisposed refers to a virtual plane containing bumps and dips which canbe generated during manufacture.

In the two-dimensional solid-state image capture device according to thethird mode of the present invention and in the two-dimensionalsolid-state image capture device in the preferred form of the fourthmode of the present invention, a color filter is disposed. The colorfilter may be a color filter that transmits particular wavelengths, suchas those of red, green, blue, cyan, magenta, and yellow. The colorfilter may be constituted by not only an organic-material-based colorfilter using an organic compound of a pigment, colorant, or the like,but also a photonic crystal, a conductor grid (a color filter having aconductor-lattice structure in which a latticed-hole structure isprovided in a conductor thin film [e.g., refer to Japanese UnexaminedPatent Application Publication No. 2008-177191]), or a thin film made ofinorganic material such as amorphous silicon. The “virtual plane” onwhich both the color filter and the polarization member are disposedrefers to a virtual plane containing bumps and dips which can begenerated during manufacture.

The two-dimensional solid-state image capture device of the presentinvention is a single-CCD-type device. Examples of the color filterarrangement include a Bayer arrangement, an interline arrangement, aG-striped RB-checkered arrangement, a G-striped andRB-complete-checkered arrangement, a checkered complementary-colorarrangement, a stripe arrangement, an oblique-stripe arrangement, aprimary-color color-difference arrangement, a field color-differencesequence arrangement, a frame color-difference sequence arrangement, aMOS arrangement, a modified MOS arrangement, a frame interleavedarrangement, and a field interleaved arrangement. For example, in thecase of the Bayer arrangement, the arrangement may be such that red,green, and blue color filters are disposed in corresponding threesub-pixel regions of 2×2 sub-pixel regions and the polarization member,not a color filter, is disposed in the remaining one sub-pixel region inwhich a green color filter is typically supposed to be disposed. In thecase of the Bayer arrangement, alternatively, the arrangement may besuch that red, green, and blue color filters are disposed incorresponding three sub-pixel regions of 2×2 sub-pixel regions and agreen color filter and the polarization member are disposed in theremaining one sub-pixel region. When color separation or spectroscopy isnot intended or when a photoelectric conversion element is intrinsicallysensitive to a particular wavelength, the filter may be eliminated. Forthe sub-pixel region in which no color filter is disposed, a transparentresin layer, instead of the color filter, may be provided in order toensure flatness with the sub-pixel regions in which the color filtersare disposed.

In the polarization-light data processing method for the two-dimensionalsolid-state image capture device according to the first mode of thepresent invention, the polarization direction θ_(PL-max) in which themaximum polarization intensity (the maximum value of the polarizationcomponent intensity) I_(PL-max) of light that is incident on the pixelarea is determined as an angle θ_(max) at which the maximum value in asine function obtained based on the light intensity I_(q) is obtained.The sine function in this case can be determined based on, for example,a Fourier analysis method or a least-squares method. The sine functionand a cosine function are equivalent to each other.

The two-dimensional solid-state image capture device according to thefirst mode of the present invention may be implemented as afrontside-illuminated two-dimensional solid-state image capture device.The two-dimensional solid-state image capture device according to thesecond to fourth modes of the present invention and the two-dimensionalsolid-state image capture device in the polarization-light dataprocessing method according to the first and second modes of the presentinvention may be implemented as frontside-illuminated two-dimensionalsolid-state image capture devices or backside-illuminatedtwo-dimensional solid-state image capture devices. These two-dimensionalsolid-state image capture devices can be applied to, for example,digital still cameras, video cameras, and camcorders.

In general, wire-grid (conductor-lattice) polarization members have aone-dimensional or two-dimensional lattice structure made of conductivematerial. As shown in a conceptual diagram in FIG. 13, when theformation pitch P₀ of the wire grid is significantly smaller than thewavelength of incident electromagnetic waves, electromagnetic waves thatoscillate in a plane parallel to a direction in which the wire gridextends are selectively reflected or absorbed by the wire grid.Consequently, although the electromagnetic waves that reach thepolarization member contain vertically polarized components andhorizontally polarized components, electromagnetic waves that havepassed through the wire grid have linear polarization light in whichvertically polarized components are dominant. In the case of avisible-light wavelength band, when the formation pitch P₀ of the wiregrid is substantially the same as or smaller than the wavelength ofelectromagnetic waves that are incident on the wire grid, thepolarization components polarized along the plane parallel to thewire-grid extension direction are reflected or absorbed by the surfaceof the wire grid. On the other hand, it is considered that, whenelectromagnetic waves having polarization components polarized along aplane perpendicular to the wire-grid extension direction are incident onthe wire grid, an electric field that has propagated on the surface ofthe wire grid causes an electromagnetic wave having the same wavelengthas the incident wavelength to be re-radiated from the backside of thewire grid. An interesting phenomenon that light with a longer wavelengththan the cut-off frequency determined by the formation pitch P₀ of thewire grid is transmitted under a condition that wavelength of theincident electromagnetic wave and the wire-grid period structure satisfya dispersion relationship for exciting surface plasmon polaritons hasalso been proposed (T. W. Ebbesen et al., Nature, vol. 391, p 667,1998). In addition, in the vicinity of the polarization member having aperiodic structure equivalent to a visible-light wavelength (i.e., in anarea located at a shorter distance from the wire grid than thewavelength of the electromagnetic wave), surface plasmon polaritons aregenerated as a result of coupling of electromagnetic waves withpolarized charge or electrons in material contained in the wire grid.Thus, the electric field changes abruptly to thereby produce near-fieldlight, which is non-propagating light. Although near-field light hasonly a range comparable to electromagnetic waves, a numeric-simulationresult of near-field light forming a very strong electric field is alsoreported (L. Salomon et al., Physical Review Letters, Vol. 86, No. 6, p1110, 2001). The polarization member in the two-dimensional solid-stateimage capture device of the present invention is implemented by such awire-grid (conductor-lattice) polarization member.

First Embodiment

A first embodiment relates to a two-dimensional solid-state imagecapture device according to a first mode and a fourth mode of thepresent invention and to a polarization-light data processing method forthe two-dimensional solid-state image capture device according to thefirst mode of the present invention. FIGS. 1A and 1B show partialschematic cross-sectional views of the two-dimensional solid-state imagecapture device in the first embodiment, FIGS. 5 to 9 schematically showplan layout views of sub-pixel regions 120 in the first embodiment, andFIGS. 4A and 4B are partial plan views of a polarization member 130.

In a two-dimensional solid-state image capture device in the firstembodiment or each of the second to fourth embodiments described below,multiple pixel areas are generally arranged in a two-dimensional matrixin an X direction and a Y direction and each pixel area is constitutedby multiple (M₀) sub-pixel regions 120, where M₀=4 in the embodiment.Each sub-pixel region 120 has a photoelectric conversion element (alight receiving element) 21.

The polarization member 130 has multiple strip-shaped conductivelight-shielding material layers 31 and slit areas 32 provided thestrip-shaped conductive light-shielding material layers 31, as shown inFIGS. 4A and 4B. The polarization member 130 transmits light having apolarization component in a direction perpendicular to a direction inwhich the strip-shaped conductive light-shielding material layers 31extend and suppresses transmission of light having a polarizationcomponent in a direction parallel to the direction in which thestrip-shaped conductive light-shielding material layers 31 extend, asillustrated in a conceptual view in FIG. 13. That is, the wire-gridpolarization member 130 is sensitive to polarization components in thedirection perpendicular to the direction in which the strip-shapedconductive light-shielding material layers 31 extend and has nosensitivity to polarization components in the direction parallel to thedirection in which the strip-shaped conductive light-shielding materiallayers 31 extend. The polarization member 130 obtains polarizationcomponents in the direction perpendicular to the direction in which thestrip-shaped conductive light-shielding material layers 31 extend andeliminates polarization components in the direction parallel to thedirection in which the strip-shaped conductive light-shielding materiallayers 31 extend.

Now, a description is given in conjunction with a two-dimensionalsolid-state image capture device according to the first mode of thepresent invention. In the two-dimensional solid-state image capturedevice in the first embodiment, the polarization member 130 is disposedat the light incident side of at least one (one sub-pixel region 120 inthe embodiment, because of m₀=1) of the sub-pixel regions 120constituting each pixel area. In addition, each sub-pixel region 120 hasat least one wiring layer 25 for controlling an operation of thephotoelectric conversion element 21. The polarization member 130 and thewiring layer 25 are made of the same material and are disposed on thesame virtual plane.

A description is now given in conjunction with a two-dimensionalsolid-state image capture device according to the fourth mode of thepresent invention or a two-dimensional solid-state image capture devicein the polarized data processing method according to the first mode ofthe present invention. In the first two-dimensional solid-state imagecapture device in the first embodiment, the polarization member 130 isdisposed at a light-incident side of one of the sub-pixel regions 120constituting each pixel area. A pixel-area group is constituted by Q₀pixel areas (where Q₀≦3, and Q₀=4 in the embodiment) and satisfies

θ_(q)=θ₁+(180/Q)×(q−1) (degree),

where Q indicates a positive integer (where 3≦Q≦Q₀ and Q=1 in thepresent embodiment), θ₁ indicates an angle defined by a predetermineddirection and a direction in which the strip-shaped conductivelight-shielding material layers extend in the polarization member in thesub-pixel region included in the q-th pixel area (where q=1), and θ_(q)indicates an angle defined by a predetermined direction and a directionin which the strip-shaped conductive light-shielding material layersextend in the polarization member in the sub-pixel region included inthe q-th pixel area (where 2≦q≦Q) selected from the Q−1 pixel areasselected from the pixels areas other than the first pixel area. Morespecifically, the following is given:

θ₂=θ₁+45 (degree),

θ₃=θ₁+90 (degree), and

θ₄=θ₁+135 (degree).

In the embodiment, the photoelectric conversion element 21 isimplemented as an electric-field amplifying image sensor (e.g., a CMOSimage sensor). The two-dimensional solid-state image capture devicesshown in FIGS. 1A and 1B are frontside-illuminated two-dimensionalsolid-state image capture devices. The polarization member 130 and thewiring layer 25 contain aluminum (Al). In the two-dimensionalsolid-state image capture device in the first embodiment or each of thesecond to fourth embodiments described below, electromagnetic wavesdetected (received) by the photoelectric conversion element 21 arevisible light. Each sub-pixel region 120 has a color filter 22, asappropriate. In the frontside-illuminated two-dimensional solid-stateimage capture devices shown in FIGS. 1A and 1B, light focused by alight-focusing element 26 is guided to the photoelectric conversionelement 21 through the color filter 22, a smoothing layer 24, thepolarization member 130, and an opening area of a light-shielding layer23. The smoothing layer 24 is made of transparent material, such assilicon dioxide (SiO₂) or (silicon nitride) SiN, and the light-shieldinglayer 23 is made of copper (Cu) or aluminum (Al). The light isphotoelectrically converted into electrical change, which is stored andis then read out as an electrical signal. A substrate 11 may be asilicon substrate. The photoelectric conversion element 21 is providedin the substrate 11. The light focusing element 26 may be implemented bynot only an on-chip convex microlens but also a sub-wavelength lens(SWLL) having a periodic structure with a physical scale that is smallerthan the wavelength of electromagnetic waves (e.g., visible light) thatare incident on the photoelectric conversion element 21. In the exampleshown in FIG. 5, the sub-pixel region having the polarization member 130has no color filter.

In the polarization member 130, the formation pitch P₀ of thestrip-shaped conductive light-shielding material layers 31, the widthW_(s) of the slit areas 32, the width W_(c) of the strip-shapedconductive light-shielding material layers 31, and the thickness t₀ ofthe strip-shaped conductive light-shielding material layers 31 may beset such that P_(s)=100 nm, W_(s)=50 nm, W_(c)=50 nm, and t₀=50 nm, butare not limited thereto. Each slit area 32 may have an elongatedrectangular shape in plan view, as shown in FIG. 4A, or may have a setof rectangular openings, as shown in FIG. 4B. In the latter case,however, it is necessary that the dimension of the longitudinal axis ofeach rectangle be significantly larger than the effective wavelength(λ₀/n₀) of light passing through the slit areas 32. The slit areas 32are filled with the same material as the material contained in thesmoothing layer 24.

FIGS. 5 to 9 and FIGS. 10 to 12, which are described below, show planlayout views of the sub-pixel regions 120. In FIGS. 5 to 12, regionsdenoted by R represent sub-pixel regions having red color filters (i.e.,red display sub-pixel regions R), regions denoted by G representsub-pixel regions having green color filters (i.e., green displaysub-pixel regions G), regions denoted by B represent sub-pixel regionshaving blue color filters (i.e., blue display sub-pixel regions B), andregions denoted by W represent sub-pixel regions having no color filters(i.e., white display sub-pixel regions W). In the first to fourthembodiments, the red display sub-pixel regions R, the green displaysub-pixel regions G, and the blue display sub-pixel regions B have nopolarization members 130. Each white display sub-pixel region W hatchedby horizontal lines is included in a first (q=1) pixel area and has thepolarization member, each white display sub-pixel region W hatched by45° oblique lines is included in a second (q=2) pixel area and has thepolarization member, each white display sub-pixel region W hatched byvertical lines is included in a third (q=3) pixel area and has thepolarization member, and each white display sub-pixel region W hatchedby 135° oblique lines is included in a fourth (q=4) pixel area and hasthe polarization member. Each area surrounded by dotted lines representsa pixel area and an area surrounded by a dashed-dotted line represents apixel-area group. The illustrated color-filter arrangement is basicallya Bayer arrangement. However, red, green, and blue color filters aredisposed in corresponding three sub-pixel regions of 2×2 sub-pixelregions, no color filter is disposed in the remaining one sub-pixelregion, and the polarization member 130 is disposed in the remaining onesub-pixel region.

Polarization information is used in, for example, a special photographymode in which, for example, reflection light is eliminated. In general,a spatial resolution that is the same as that for typical image captureis not necessary in many cases. In addition, the sub-pixel region 120having the polarization member 130 has a structure in which iteliminates some light and thus has a sensitivity that lower than that ofthe other sub-pixel regions. Arrangement of the polarization members 130at a particular period as shown in FIG. 5 makes it possible to increasethe rate of the sub-pixel regions having no polarization areas and alsomakes it possible to minimize a decrease in the overall sensitivity ofthe two-dimensional solid-state image capture device. Although thesub-pixel regions 120 having the polarization members 130 are arrangedwith one sub-pixel region interposed therebetween in the X and Ydirections in FIG. 5, they may be arranged with two or three sub-pixelregions interposed therebetween. The sub-pixel regions 120 having thepolarization members 130 may also be arranged in a hound's toothpattern.

In the polarization-light data processing method for the two-dimensionalsolid-state image capture device, I_(q) denotes a light intensity oflight that is incident on the sub-pixel region that has the polarizationmember and that is included in the q-th pixel area (where q=1, 2, . . ., Q). A polarization direction θ_(PL-max) in which a maximumpolarization intensity (i.e., a maximum value of polarization componentintensity) I_(PL-max) of light that is incident on the pixel area isobtained is determined as an angle θ_(max) at which a maximum value in asine function obtained based on the light intensity I_(q) is obtainedand the determined maximum value and a minimum value in the sinefunction are used as the maximum polarization intensity max and theminimum polarization intensity (the minimum value of the polarizationcomponent intensity) I_(PL-min) of the light that is incident on thepixel area.

Specifically, one pixel-area group is constituted by four (Q₀=4) pixelareas, each having one sub-pixel region 120 having the polarizationmember 130. Accordingly, in the pixel-area group, four incident lightintensities I_(q) (q=1, 2, 3, 4) can be obtained.

Since the electromagnetic waves are oscillating waves, electric fields∈_(x) and ∈_(y) at time t and position z in an X-Y plane perpendicularto a Z axis along which the electromagnetic waves travel can be give by:

∈_(x) =E _(x)·exp[i(k·z−ω·t+δ ₁)]

∈_(y) =E _(y)·exp[i(k·z−ω·t+δ ₂)]

where E_(x) denotes an amplitude of components in the X direction, E_(y)denotes an amplitude of components in the Y direction, k denotes a phaseconstant and is 2π/λ, ω represents an angular frequency of theelectromagnetic waves, δ₁ denotes an initial phase of the components inthe X direction, and δ₂ denotes an initial phase of the components inthe Y direction.

The electromagnetic waves detected are a combination of oscillatingwaves which can be expressed by those sine functions. Thus, when aparticular linear polarization component, circular polarizationcomponent, or elliptical polarization component is prominent, theintensity of electromagnetic waves observed using the polarizationmember 130 in the two-dimensional solid-state image capture device inthe first embodiment can be expressed by a sine function in which oneperiod corresponds to an azimuth of 360°. On the other hand, when thepolarization components of the electromagnetic waves are completelyrandom, no particular polarization occurs and thus the electromagneticwave intensity becomes independent from the direction of thepolarization members.

That is, as described above, the light intensities I_(q) obtained fromthe sub-pixel regions 120 having the polarization members are expressedby a sine function and an angle θ_(max) when the maximum value in thesine function is obtained can be used as the polarization directionθ_(PL-max) in which the maximum polarization intensity (the maximumvalue of the polarization component intensity) I_(PL-max) is obtained.In addition, the determined maximum value and the minimum value in thesine function ca be used respectively as the maximum polarizationintensity I_(PL-max) and the minimum polarization intensity (the minimumvalue of the polarization component intensity) I_(PL-min) of light thatis incident on the pixel area. The polarization component intensityI_(PL) can be expressed by:

I _(PL) =I _(PL-max) −I _(PL-min))/(I _(PL-max) +I _(PL-min)).

As shown in FIG. 5, one red display sub-pixel region R is surrounded byeight sub-pixel regions, i.e., a green display sub-pixel region G, ablue display sub-pixel region B, a white display sub-pixel region W, ablue display sub-pixel region B, a green display sub-pixel region G, ablue display sub-pixel region B, a white display sub-pixel region W, anda blue display sub-pixel region B, clockwise from 12 o'clock. One greendisplay sub-pixel region G is surrounded by eight sub-pixel regions,i.e., a red display sub-pixel region R, a white display sub-pixel regionW, a blue display sub-pixel region B, a white display sub-pixel regionW, a red display sub-pixel region R, a white display sub-pixel region W,a blue display sub-pixel region B, and a white display sub-pixel regionW, clockwise from 12 o'clock. One blue display sub-pixel region B issurrounded by a white display sub-pixel region W, a red displaysub-pixel region R, a green display sub-pixel region G, a red displaysub-pixel region R, a white display sub-pixel region W, a red displaysub-pixel region R, a green display sub-pixel region G, and a reddisplay sub-pixel region R. One white display sub-pixel region W issurrounded by a blue display sub-pixel region B, a green displaysub-pixel region G, a red display sub-pixel region R, a green displaysub-pixel region G, a blue display sub-pixel region B, a green displaysub-pixel region G, a red display sub-pixel region R, and a greendisplay sub-pixel region G.

In the polarization-light data processing method in the firstembodiment, the direction and the intensity of polarization componentsof light that is incident on, of the sub-pixel regions constituting eachpixel area, the sub-pixel region having no polarization member arecorrected based on the light intensity I_(PL-max) and/or the lightintensity I_(PL-min). In addition, the direction and the intensity ofthe polarization components of light that is incident on, of thesub-pixel regions constituting each pixel area, the sub-pixel regionhaving no polarization member are corrected based on the light intensityI_(PL-max) and/or the light intensity derived from the sub-pixel regionsthat have the polarization members and that are located in the vicinityof the sub-pixel region having no polarization member.

That is, the direction and the intensity of polarization components oflight that is incident on the green display sub-pixel region G arecorrected based on the light intensity I_(PL-max) and the lightintensity I_(PL-min) derived from the white display sub-pixel regions Wlocated in the vicinity of the green display sub-pixel region G. Morespecifically, as shown in FIG. 6, the polarization information of thegreen display sub-pixel region G are obtained from a polarizationdirection and a polarization component intensity determined from thepolarization information of four neighborhood white display sub-pixelregions W (i.e., four white display sub-pixel regions W located to theupper right, lower right, lower left, and upper left of the greendisplay sub-pixel region G). On the basis of the light intensities I_(q)obtained from the four white display sub-pixel regions W, θ_(PL-max),I_(PL-max), I_(PL-min), and I_(PL), of the green display sub-pixelregion G can be obtained.

Similarly, the direction and the intensity of polarization components oflight that is incident on the blue display sub-pixel region B arecorrected based on the light intensity I_(PL-max) and the lightintensity I_(PL-min) derived from the white display sub-pixel regions Wlocated in the vicinity of the blue display sub-pixel region B. Morespecifically, as shown in FIG. 7, the polarization information of theblue display sub-pixel region B is obtained from a polarizationdirection and a polarization component intensity determined from thepolarization information of four neighborhood white display sub-pixelregions W (i.e., four white display sub-pixel regions W locatedimmediately above, immediately below, to the lower left of, and to theupper left of the blue display sub-pixel region B). The polarizationinformation of the blue display sub-pixel region B may be obtained froma polarization direction and a polarization component intensitydetermined from the polarization information of a total of sixneighborhood white display sub-pixel regions W further including twoneighborhood white display sub-pixel regions W located to the lowerright and upper right of the blue display sub-pixel region B. On thebasis of the light intensities I_(q) obtained from the four (or six)white display sub-pixel regions W, θ_(PL-max), I_(PL-max), I_(PL-min),and I_(PL) of the blue display sub-pixel region B can be obtained.

Similarly, the direction and the intensity of polarization components oflight that is incident on the red display sub-pixel region R arecorrected based on the light intensity I_(PL-max) and the lightintensity I_(PL-min) derived from the white display sub-pixel regions Wlocated in the vicinity of the red display sub-pixel region R. Morespecifically, as shown in FIG. 8, the polarization information of thered display sub-pixel region R is obtained from a polarization directionand a polarization component intensity determined from the polarizationinformation of four neighborhood white display sub-pixel regions W(i.e., four white display sub-pixel regions W located to the upperright, immediately right, immediately left, and upper left of the reddisplay sub-pixel region R). The polarization information of the reddisplay sub-pixel region R may be obtained from a polarization directionand a polarization component intensity determined from the polarizationinformation of a total of six neighborhood white display sub-pixelregions W further including two neighborhood white display sub-pixelregions W located to the lower right and lower left of the red displaysub-pixel region R. On the basis of the light intensities I_(q) obtainedfrom the four (or six) white display sub-pixel regions W, θ_(PL-max),I_(PL-max), I_(PL-min), and I_(PL) of the red display sub-pixel region Rcan be obtained.

Similarly, as shown in FIG. 9, the polarization information of the whitedisplay sub-pixel region W located at the center is obtained from apolarization direction and a polarization-light component intensityobtained from the polarization information of three neighborhood whitedisplay sub-pixel regions W (i.e., three white display sub-pixel regionsW located immediately above, to the immediately left of, and to theupper left of the white display sub-pixel region W) and the polarizationinformation of the white display sub-pixel region W located at thecenter. The polarization information of the white display sub-pixelregion W located at the center may also be obtained from a polarizationdirection and a polarization component intensity determined from thepolarization information of a total of eight neighborhood white displaysub-pixel regions W further including five white display sub-pixelregions W located to the upper right of, to the immediate right of, tothe lower right of, immediately below, and to the lower left of thewhite display sub-pixel region W. On the basis of the light intensitiesI_(q) obtained from the three (or eight) white display sub-pixel regionsW, θ_(PL-max), I_(PL-max), I_(PL-min), and I_(PL) of the white displaysub-pixel region W located at the center can be obtained. FIG. 9illustrates polarization information of the white sub-pixel regions Wlocated at only two centers.

That is, as a result of the above-described processes, the polarizationcomponent intensities and the polarization directions of the sub-pixelregions can be obtained, and also a two-dimensional map of polarizationlight component intensities (I_(PL)), a two-dimensional map of azimuths(θ) of polarization light, a two-dimensional map of maximumpolarization-light intensities (the maximum values of polarizationcomponent intensities) I_(PL-max), and a two-dimensional map of minimumpolarization intensities (the minimum values of polarization componentintensities) I_(PL-min) can be obtained. In this case, with respect tothe sub-pixel region having no polarization member 130, it can beregarded that all polarization components in an azimuth of 0° to 180°are integrated for detection. Thus, the luminance value (I_(total)) ofthe sub-pixel region having no polarization member 130 can be regardedas being equal to a value obtained by dividing an average intensity(I_(ave)) of polarization components by a directional capability (η) ofthe polarization member 130. In this case, the following relationship issatisfied:

I _(PL-max) =I _(ave)·(1+I _(PL))

I _(PL-min) =I _(ave)·(1−I _(PL))

Since the directional capability (η) of the polarization member is acharacteristic value that is independent from the azimuth of thepolarization member, it can be presumed that the intensity ratio ofI_(total) to I_(ave) becomes a constant. When the proportional constantis assumed to be 1, multiplying I_(total) by (1+I_(PL)) and (1−I_(PL))makes it possible to reproduce an image having I_(PL-max) and I_(PL-min)in each sub-pixel region. With respect to the sub-pixel regions 120having the polarization members 130, an intensity that does not involvethe polarization information can also be derived through interpolationof the intensities of the surrounding sub-pixel regions. Thus, thetwo-dimensional map of I_(total) for typical image capture (i.e., forphotography that does not use the polarization information) can beobtained in the same manner.

The process for restoring information of the sub-pixel region, locatedat the center, from the surrounding sub-pixel regions can be realized bya scheme and algorithm that are similar to those for color informationdemosaicing. Thus, an image containing the polarization information anda general image may be demosaiced and reconstructed based on analgorithm other than the above-described algorithm. The above-describedpositional relationship between each sub-pixel region and thus the whitedisplay sub-pixel regions W is illustrative and can be modified asappropriate. In addition, the polarization information of the sub-pixelregions having no polarization members is determined from thepolarization information of four neighborhood white display sub-pixelregions W, as described above, and the positions of the four whitedisplay sub-pixel regions W are also illustrative and thus can bemodified as appropriate.

Instead of the sub-pixel-region plan layout shown in FIG. 5, anarrangement as in a sub-pixel-region plan layout shown in FIG. 10 mayalso be employed. The configuration in FIG. 10 has basically a Bayercolor-filter arrangement and has a configuration in which red, green,blue, and green color filters are disposed in a pixel area constitutedby four (2×2) sub-pixel regions and the polarization member is disposedin one of the four sub-pixel regions constituting each pixel area. InFIG. 10, a green display sub-pixel region G located at row b and column3 is expressed by a green display sub-pixel region G(b, 3).

The light intensity I_(q) of light that is incident on the sub-pixelregion having the polarization member, the sub-pixel region beingincluded in the q-th pixel area (where q=1, 2, . . . , Q), is correctedbased on the light intensities of light that is incident on theneighborhood sub-pixel regions that have no polarization members andthat have the same detection wavelength band as the sub-pixel regionhaving the polarization member.

Specifically, for example, with respect to the red display sub-pixelregion R having the polarization member 130, the average value of thelight intensities of the surrounding eight red display sub-pixel regionsR having no polarization members 130 can be used as the light intensityof the red display sub-pixel region R when it is assumed to have nopolarization member 130. For example, with respect to the red displaysub-pixel region R(g, 7), the average value of the light intensities ofthe red display sub-pixel region R(g, 5), the red display sub-pixelregion R(i, 5), the red display sub-pixel region R(i, 7), the reddisplay sub-pixel region R(i, 9), the red display sub-pixel region R(g,9), the red display sub-pixel region R(e, 9), the red display sub-pixelregion R(e, 7), and the red display sub-pixel region R(e, 5) may be usedas the light intensity of the red display sub-pixel region R(g, 7) whenit is assumed to have no polarization member 130. On the basis of thedetermined average value of the light intensities and the lightintensity of the red display sub-pixel region R(g, 7) having thepolarization member 130, the polarization component intensity of the reddisplay sub-pixel region R(g, 7) can also be obtained. With respect tothe green display sub-pixel region G having the polarization member 130and the blue display sub-pixel region B having the polarization member130, the average value of the light intensities thereof can be obtainedas in the manner described above. Thus, θ_(PL-max), I_(PL-max),I_(PL-min), and I_(PL) of one pixel-area group can be obtained from, forexample, the red display sub-pixel region R(a, 1), the green displaysub-pixel region G(c, 1), the blue display sub-pixel region B(c, 4), andthe green display sub-pixel region G(a, 4). The same applies to theother pixel-area groups.

θ_(PL-max), I_(PL-max), I_(PL-min), and I_(PL) of the pixel area [e.g.,the pixel area constituted by the red display sub-pixel region R(e, 1),the green display sub-pixel region G(f, 1), the blue display sub-pixelregion B(f, 2), and the green display sub-pixel region G(e, 2)] disposedbetween the pixel-area groups can be determined as the average values ofθ_(PL-max), I_(PL-max), I_(PL-max), and I_(PL) of two pixel-area groupsdisposed at two opposite ends of the pixel area or four pixel-areagroups surrounding the pixel area.

Since the light intensity, the polarization component intensity, and thepolarization direction of each sub-pixel region can be obtained asdescribed above, for example, image data can be processed afterphotography on the basis of the polarization information. For example,performing desired processing on a portion of an image obtained byphotography of the sky or window glass, a portion of an image obtainedby photography of a water surface, or the like makes it possible toemphasize or attenuate polarization components or makes it possible toseparate polarization components and non-polarization components. Thus,it is possible to improve the image contrast and to eliminate unwantedinformation. More specifically, for example, it is possible to performsuch processing by specifying a photography mode during photographyusing a two-dimensional solid-state image capture device.

The two-dimensional solid-state image capture device in the firstembodiment or each of the second to fourth embodiments described belowcan eliminate reflection in window glass. In addition, addingpolarization information to image information also makes it possible toclarify the boundaries (contours) of multiple objects. It is alsopossible to detect the state of a road surface or an obstacle on a roadsurface. In addition, the two-dimensional solid-state image capturedevice can be applied to a variety of fields, including photography of apattern incorporating birefringence of an object, measurement ofretardation distribution, acquirement of an image under apolarized-light microscope, acquirement of a surface shape of an object,measurement of a surface texture of an object, detection of a movingobject (such as a vehicle), and meteorological observation such asmeasurement of cloud distribution.

The two-dimensional solid-state image capture device in the firstembodiment can basically be manufactured by the same method as a methodfor already available two-dimensional solid-state image capture devices,except for microfabrication of the polarization member 130. Themicrofabrication of the polarization member 130 can easily be realizedusing a technology for manufacturing semiconductor devices. Thus, themethod for manufacturing the two-dimensional solid-state image capturedevice in the first embodiment is not described below. The same appliesto the two-dimensional solid-state image capture devices in the thirdand fourth embodiments described below.

In the two-dimensional solid-state image capture device in the firstembodiment, the wiring layer and the polarization member are made of thesame material and are disposed on the same virtual plane. Accordingly,the wiring layer and the polarization member can be simultaneouslyformed in the same process by using a general semiconductor-devicemanufacturing process. Since the polarization member can be providedwithout an increase in the number of manufacturing processes, themanufacturing cost of the two-dimensional solid-state image capturedevice can be reduced. Moreover, since it is not necessary to addanother layer for the polarization member, it is possible to achieve alower-profile structure of the two-dimensional solid-state image capturedevice. The provision of the polarization member also does not involvean increase in the thickness of the two-dimensional solid-state imagecapture device. Since the thickness of the polarization member in thetwo-dimensional solid-state image capture device in the first embodimentor each of the third and fourth embodiments described below can bereduced to as small as about 0.1 μm, it is possible to achieve alower-profile structure of the two-dimensional solid-state image capturedevice.

In addition, in the two-dimensional solid-state image capture device inthe first embodiment or the second embodiment described below, thepolarization member is disposed at the light incident side of one ofmultiple (M₀) sub-pixel regions constituting each pixel area, and thus,Q polarization members (where Q≦Q₀) are disposed in one pixel-area groupconstituted by Q₀ pixel areas (where Q₀≦3). That is, only Q polarizationmembers are disposed in the total of Q₀×M₀ sub-pixel regionsconstituting one pixel-area group. Consequently, it is possible tominimize a sensitivity reduction due to the arrangement of thepolarization members in the entire pixel area. Determination of thepolarization component intensity and the polarization direction at theposition of each pixel area by performing inter-pixel-area computationprocessing makes it possible to obtain polarization information with thespatial resolution being slightly compromised, while minimizing areduction in the sensitivity. Furthermore, since only Q polarizationmembers are disposed in the total of Q₀×M₀ sub-pixel regionsconstituting one pixel-area group, the computation processing for theamount and intensity of light received by the photoelectric conversionelements does not become complicated. In addition, information of thepolarization component intensity, the polarization direction, and so oncan be obtained in real time and information of the polarizationdirection and the polarization component intensity can also be obtainedfrom a single image.

Second Embodiment

A second embodiment relates to a polarization-light data processingmethod for a two-dimensional solid-state image capture device accordingto a second mode of the present invention. The two-dimensionalsolid-state image capture device in the second embodiment may have thesame configuration as the two-dimensional solid-state image capturedevice described above in the first embodiment, and thus, a detaileddescription is not given hereinafter.

The polarization-light data processing method for the two-dimensionalsolid-state image capture device in the second embodiment is asimplified one of the polarization-light data processing method for thetwo-dimensional solid-state image capture device in the firstembodiment, thereby achieving a reduction in the amount of dataprocessing. In the polarization-light data processing method for thetwo-dimensional solid-state image capture device in the secondembodiment, I_(q) denotes the light intensity of light that is incidenton the sub-pixel region having the polarization member and constitutingthe q-th pixel area (where q=1, 2, . . . , Q). The maximum value I_(max)of the light intensities I_(q) is used as the maximum polarizationintensity I_(PL-max) f light that is incident on the pixel area, theangle θ_(q) of the pixel area where I_(max) is obtained is used as thepolarization direction θ_(PL-max) in which the maximum polarizationintensity I_(PL-max) of light that is incident on the pixel area isobtained, and the minimum value I_(min) of the light intensities I_(q)is used as the minimum polarization intensity I_(PL-min) of light thatis incident on the pixel area.

For example, for Q=6 or Q=8, a polarization component intensity and apolarization direction can be obtained with an accuracy that does notcause a problem in practice and the amount of data processing can alsobe dramatically reduced compared to the first embodiment.

Third Embodiment

A third embodiment relates to the two-dimensional solid-state imagecapture device according to the second mode of the present invention. Inthe two-dimensional solid-state image capture device in the thirdembodiment, as shown in a schematic partial cross sectional view in FIG.2A or 2B, a polarization member 230 is disposed at the light inside sideof at least one of sub-pixel regions 220 constituting each pixel area.Each sub-pixel region has a light-shielding layer 23 for controlling(restricting) incidence of light on the photoelectric conversionelement. The polarization member 230 and the light-shielding layer 23are disposed on the same virtual plane. In this case, the polarizationmember 230 is a wire-grid polarization member and is made of, forexample, aluminum (Al) or copper (Cu), and the light-shielding layer 23is made of, for example, aluminum (Al) or tungsten (W).

The two-dimensional solid-state image capture device shown in FIG. 2A isa frontside-illuminated two-dimensional solid-state image capturedevice, whereas the two-dimensional solid-state image capture deviceshown in FIG. 2B is a backside-illuminated two-dimensional solid-stateimage capture device. In the frontside-illuminated two-dimensionalsolid-state image capture device shown in FIG. 2A, light focused by alight-focusing element 26 is guided to the photoelectric conversionelement 21 through a color filter 22, a smoothing layer 24, and thepolarization member 230. The smoothing layer 24 is made of transparentmaterial, such as SiO₂ or SiN. The polarization member 230 is providedin an opening area of the light-shielding layer 23. The light isphotoelectrically converted into electrical change, which is stored andis then read out as an electrical signal. On the other hand, in thebackside-illuminated two-dimensional solid-state image capture deviceshown in FIG. 2B, light focused by a light-focusing element 26 is guidedto the photoelectric conversion element 21 through a color filter 22, asubstrate 11, and the polarization member 230, which is provided in anopening area of a light-shielding layer 23. The light isphotoelectrically converted into electrical change, which is stored andis then read out as an electrical signal. There is also a case in whichthe color filter 22 is not disposed in the sub-pixel region 220 havingthe polarization member 230.

In the third embodiment, the polarization member 230 is provided abovethe photoelectric conversion element 21 with an insulating film 231interposed therebetween. It is preferable that the thickness of theinsulating film 231 be 1×10⁻⁷ m or less and be as small as possible.When an electromagnetic wave in the range of a visual-light wavelengthto a near-infrared-light wavelength is incident on the polarizationmember 230 and the periodic structure of the strip-shaped conductivelight-shielding material layers of the polarization member 230 and thewavelength of the incident electromagnetic wave satisfy a resonancecondition, the electromagnetic wave couples with polarized charge orelectrons in the material contained in the strip-shaped conductivelight-shielding material layers to generate surface plasmon polaritons.In this state, near-field light is produced in an area defined by aclosed electric line of force of polarized charge (i.e., an area ofnon-propagating light). The near-field light can exist in only a rangecomparable to the electromagnetic wavelength and the intensity of thenear-field light becomes weak exponentially. Thus, the near-field lightcan be received (measured) by only the photoelectric conversion element21 with the ultrathin (100 nm or less) insulating film 231 interposedbetween the photoelectric conversion element 21 and the light-shieldinglayer 23. Accordingly, when a structure in which the polarization member230 and the photoelectric conversion element 21 are disposed with theinsulating film 231 interposed therebetween is employed, a smallerthickness of the insulating film 231 is more preferable.

Thus, in the two-dimensional solid-state image capture device in thethird embodiment, surface plasmon polaritons excited on the surface ofthe polarization member 230 by incident electromagnetic waves propagateand pass through the strip-shaped conductive light-shielding materiallayers 31, and the propagation light is re-radiated. The photoelectricconversion element 21 can receive the re-radiated propagation light orcan detect an abrupt electric-field change caused by polarization or thelike of the material for the conductive light-shielding material layers31.

In the two-dimensional solid-state image capture device in the thirdembodiment, the light shielding layer and the polarization member aredisposed on the same virtual plane. Accordingly, the light-shieldinglayer and the polarization member can be simultaneously formed in thesame process by using a general semiconductor-device manufacturingprocess. Since the polarization member can be provided without anincrease in the number of manufacturing processes, the manufacturingcost of the two-dimensional solid-state image capture device can bereduced. Moreover, since it is not necessary to add another layer forthe polarization member, it is possible to achieve a lower-profilestructure of the two-dimensional solid-state image capture device. Theprovision of the polarization member also does not involve an increasein the thickness of the two-dimensional solid-state image capturedevice.

The two-dimensional solid-state image capture device according to thefourth mode of the present invention described in the first embodimentcan also be applied to the two-dimensional solid-state image capturedevice described in the third embodiment, and also thepolarization-light data processing method for the two-dimensionalsolid-state image capture device according to the first or second modeof the present invention described in the first or second embodiment canbe applied to such a form.

Fourth Embodiment

A fourth embodiment relates to the two-dimensional solid-state imagecapture device according to the third mode of the present invention. Inthe two-dimensional solid-state image capture device in the fourthembodiment, as shown in a schematic partial cross sectional view in FIG.3A or 3B, a wire-grid polarization member 330 is disposed at the lightinside side of one of sub-pixel regions 320 constituting each pixel areaand color filters (not show) are disposed at the light incident sides ofthe remaining sub-pixel regions. The color filters and the polarizationmember 330 are disposed on the same virtual plane.

The two-dimensional solid-state image capture device shown in FIG. 3A isa frontside-illuminated two-dimensional solid-state image capturedevice, whereas the two-dimensional solid-state image capture deviceshown in FIG. 3B is a backside-illuminated two-dimensional solid-stateimage capture device. In the frontside-illuminated two-dimensionalsolid-state image capture device shown in FIG. 3A, light focused by alight-focusing element 26 is guided to the photoelectric conversionelement 21 through a polarization member 330, a smoothing layer 24, andan opening area of a light-shielding layer 23. The light-focusingelement 26 has an on-chip convex microlens and the smoothing layer 24 ismade of transparent material, such as SiO₂ or SiN. The light isphotoelectrically converted into electrical change, which is stored andis then read out as an electrical signal. On the other hand, in thebackside-illuminated two-dimensional solid-state image capture deviceshown in FIG. 3B, light focused by a light-focusing element 26 is guidedto the photoelectric conversion element 21 through a polarization member330, a substrate 11, and an opening area of a light-shielding layer 23.The light is photoelectrically converted into electrical change, whichis stored and is then read out as an electrical signal.

Since the color filter and the polarization member in thetwo-dimensional solid-state image capture device in the fourthembodiment are disposed on the same virtual plane, it is unlikely theheight of one sub-pixel region having the polarization member and theheight of another sub-pixel region having the color filter differ fromeach other. Moreover, since it is not necessary to add another layer forthe polarization member, it is possible to achieve a lower-profilestructure of the two-dimensional solid-state image capture device. Theprovision of the polarization member also does not involve an increasein the thickness of the two-dimensional solid-state image capturedevice.

The two-dimensional solid-state image capture device according to thefourth mode of the present invention described in the first embodimentcan also be applied to the two-dimensional solid-state image capturedevice described in the fourth embodiment, and also thepolarization-light data processing method for the two-dimensionalsolid-state image capture device according to the first or second modeof the present invention described in the first or second embodiment canbe applied to such a form.

Although preferred embodiments of the present invention have beendescribed above, the present invention is not limited to theembodiments. In the embodiments described above, the polarization memberis exclusively used to obtain the polarization information of thesolid-state image capture element that is sensitive to a visible lightwavelength band. However, when the photoelectric conversion element (thelight-receiving element) is sensitive to infrared or ultraviolet light,increasing or reducing the formation pitch P₀ of the strip-shapedconductive light-shielding material layers so as to correspond to thesensitivity allows the polarization member to function in an arbitrarywavelength band.

The plan layout of the sub-pixel regions in the two-dimensionalsolid-state image capture devices according to the first to third modesof the present invention described in the first, third, and fourthembodiments are not limited to those described with reference to FIGS. 5and 10. For example, the plan layout of the sub-pixel regions may be aplan layout illustrated in FIG. 11 or 12. For a CMOS solid-state imagecapture device having the plan layout shown in FIG. 11, it is possibleto employ a 2×2 pixel sharing scheme in which 2×2 sub-pixel regionsshare a selecting transistor, a reset transistor, and an amplifyingtransfer. In an image capture mode in which no pixel summation isperformed, image capture involving the polarization information isperformed, and in a mode in which charges stored in 2×2 sub-pixelregions are subjected to summation using floating diffusions, a generalcaptured image into which all polarization components are integrated canbe provided. In the plan layout shown in FIG. 12, the polarizationmembers in one direction are arranged in 2×2 sub-pixel regions. Thus,inter-pixel discontinuity in the conductor lattice is less likely tooccur, thereby making it possible to achieve high-quality polarizationimage capture.

Forming two types of transparent substrate on a transparent substrate ora base by using the polarization members described in the embodimentsand allocating the transparent substrates, in an image display apparatussuch as a television receiver, to corresponding pixels for the right eyeand the left eye makes it possible to provide an image for stereoscopicvision. In addition, for example, embedding multiple images in a singleimage enables multiple people to view different images (programs) at thesame time. In addition, fabricating, in two layers in the recordingmedium in a DVD or Blu-ray optical-disk system, a pit-and-bump structurefor vertical polarization and a pit-and-bump structure for horizontalpolarization and using a laser polarized vertically and horizontallyallows twice the amount of information to be recorded with the samesize. The present invention can also be applied to opticalcommunications equipment and so on.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application JP 2009-114809 filedin the Japan Patent Office on May 11, 2009, the entire content of whichis hereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1-14. (canceled)
 15. An imaging device comprising: a plurality of pixelareas arranged in a two-dimensional matrix, each pixel area of theplurality of pixel areas being constituted by a plurality of sub-pixelregions, each sub-pixel region of the plurality of sub-pixel regionshaving a photoelectric conversion element; a polarization memberdisposed on a light incident side of at least one of the plurality ofsub-pixel regions; and a color filter disposed on the light incidentside of at least one of the plurality of sub-pixel regions, wherein thecolor filter is different from the polarization member, wherein thepolarization member has strip-shaped conductive light-shielding materiallayers, wherein the polarization member is configured to transmit lighthaving a polarization component in a direction perpendicular to adirection in which the strip-shaped conductive light-shielding materiallayers extend and to block light having a polarization component in adirection parallel to the direction in which the strip-shaped conductivelight-shielding material layers extend, wherein each sub-pixel regionfurther has a light-shielding layer configured to shield incidence oflight on the photoelectric conversion element, and wherein thepolarization member and the light-shielding layer are disposed on acommon plane.
 16. The imaging device according to claim 15, wherein eachsub-pixel region further has a wiring layer configured to control anoperation of the photoelectric conversion element.
 17. The imagingdevice according to claim 16, wherein the polarization member and thewiring layer are made of the same material and are disposed on the samecommon plane.
 18. The imaging device according to claim 15, wherein thepolarization member has slit areas provided between the strip-shapedconductive light-shielding material layers.
 19. The imaging deviceaccording to claim 15, wherein the color filter is disposed at the lightincident side of a sub-pixel region in which no polarization member isdisposed.
 20. The imaging device according to claim 15, wherein thecolor filter and the polarization member are disposed on the same commonplane.
 21. The imaging device according to claim 15, wherein a pixelarea group is constituted by Q₀ pixel areas (where Q₀≦3) and satisfiesθ_(q)=θ₁+(180/Q)×(q−1) (degree), where Q indicates a positive integer(where 3≦Q≦Q₀), θ₁ indicates an angle defined by a predetermineddirection and a direction in which the strip-shaped conductivelight-shielding material layers extend in the polarization member in thesub-pixel region included in the q-th pixel area (where q=1), and θ_(q)indicates an angle defined by a predetermined direction and a directionin which the strip-shaped conductive light-shielding material layersextend in the polarization member in the sub-pixel region included inthe q-th pixel area (where 2≦q≦Q) selected from the Q−1 pixel areasselected from the pixels areas other than the first pixel area.
 22. Theimaging device according to claim 21, wherein Q is 4.